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Fan Speed Control HD 4870?

01-29-2010, 06:59 PM

Hi there! I am relatively new to the Linux scene. I started with distros like Ubuntu and Fedora, of course, but I have recently switched to Sabayon to start trying my hand in a Gentoo flavor...that is beside the point though.

I am currently running the ATI proprietary driver on my HD 4870, and I get absolutely terrible 2d performance (window tearing, slow, etc); I only use Linux for casual browsing, learning, and some programming so good 2d performance is all I really want! I would like to switch to an open source driver because I hear the 2d performance is significantly better, but I need to have some way of implementing manual fan control. This card gets super hot if I don't crank up the fan speed. Is there anything like this in the radeon driver, or am I basically stuck with fglrx for the time being? Thank you!

The fan controllers are normally pre-set with a temperature/fan speed profile by the BIOS at power-up, then the controller chip handles fan speed changes autonomously from that point. I think you're saying that the profile loaded at power-up isn't working for you ? What reported temps and fan speed are you seeing with fglrx ?

The foundation capabilities (KMS, I2C support) required for fan control seem to be mostly in place but not 100% sure about that, maybe one of the devs can jump in.

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The default fan setup should be adequate for the default clocks used by the open source drivers. The basic infrastructure (i2c, power table parsing) is pretty much in place at this point. Prior to r6xx, fan controllers and thermal chips were always external i2c chips. On r6xx+, the card can use an external chip or the on board controller. It depends how the oem wired it up. But, at the moment, there's no code yet to actually adjust the fan or get the temperature from the thermal chip.

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While the default fan speed setup may be adequate temperature wise for the clocks used by the oss drivers, it may not be noise wise. The bios of my HD 5750 seems to be setup with a default minimum fan speed of 36%, which is way too loud. I have to crank it down by 10% to get my silent pc back.

So in short, I definitely want to see some fan speed control and temperature monitoring in the OSS drivers.

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I'm having the same problem with my 4850. Too noisy and too hot, mostly the former. Whatever fglrx is doing is close to optimal as I rarely hear the fan. And with aticonfig the fan can be adjusted manually. I don't know what's involved in developing fan control software, but fglrx seems to have had it for a while whereas in the Open Source sector it doesn't even seem to be on the radar. As I don't use 3D this is the one thing that's forcing me to stick with the proprietary driver.

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nbi1, if your card is too noisy *and* too hot that's not going to be fixed with fan control software. You're probably seeing a difference in power management effectiveness, which in turn allows the fan to be slowed down and/or the chip to run cooler.

Are you running with KMS code or with user modesetting ? If the latter, are you using ForceLowPowerMode and other power saving options ?

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nbi1, if your card is too noisy *and* too hot that's not going to be fixed with fan control software. You're probably seeing a difference in power management effectiveness, which in turn allows the fan to be slowed down and/or the chip to run cooler.

Are you running with KMS code or with user modesetting ? If the latter, are you using ForceLowPowerMode and other power saving options ?

The 2.6.32 kernel I built is defaulting to user modesetting. It's no big deal to rebuild the kernel, I just need to know the approach that will allow me to control the HD4850's temp & fan speed. At a minimum I'd like to see the same behavior as under fglrx.

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As a *minimum* you'd like to see the same behaviour as fglrx ? Geez, you don't want much

User modesetting is fine. Do you have Option "ForceLowPowerMode" "on" and Option "DynamicPM" "on" ? If not, add them to the device section of your xorg.conf.

Running "man radeon" will give you more info about the options.

Ok, let me rephrase. The same default behavior for temp and speed control. Whatever fglrx is doing in that context it's doing it right. I don't think it's outlandish to presuppose the OSS driver authors would keep those performance attributes of the proprietary driver that are good. Alles klar?

The Radeon man page has absolutely nothing about the options you mention. In fact the man page was one of the first places I looked to resolve the speed/temp problem.

I've just about had it with ATI. The driver nonsense just never ends. Two GTX 260s in SLI is starting to look pretty good.